Jars of yellow rice wine are stored in Shaoxing, East China's Zhejiang province. [Photo/Tide News]

Shaoxing-based yellow rice wine producer Shao Xing Jiu transmitted 600 metric tons of production wastewater via a dedicated pipeline to Shangyu Water Treatment Development Company on Aug 26.

There, the wastewater — once a costly environmental burden — is now repurposed as a high-quality carbon source for use in municipal sewage treatment.

This marks the official launch of Zhejiang province's first pilot project for carbon reduction and pollution control in the rice wine sector. The project completed its first targeted transmission of industrial wastewater last month.

Rice wine producers have long struggled with large volumes of high-organic-content wastewater and the associated treatment costs.

According to Zheng Yiming, deputy general manager of Shao Xing Jiu, the company produces 58,000 tons of rice wine and nearly 1,500 tons of spirits annually, generating around 1,000 tons of wastewater per day. To meet discharge standards, the firm has had to spend nearly 3 million yuan ($420,000) each year on pre-treatment.

Due to its high organic load, rice wine wastewater is also a readily biodegradable carbon source. "In biological wastewater treatment, carbon is an essential nutrient for microbial activity and pollutant degradation. Sewage plants typically spend heavily on external carbon additives," said Xu Jiangjun, general manager of Shangyu Water Treatment.

By using rice wine production wastewater as a supplementary carbon source, both partners aim to reduce treatment costs and lower emissions. The collaboration is expected to cut carbon emissions by more than 4,200 tons annually and save over 3.5 million yuan in wastewater treatment costs.